This action research study examined how faculty development workshops affected how testing grade level teachers disaggregate standardized data. It also examined how teachers used the information to improve communication and classroom instruction. The rationale for the study was that teachers were asked to be data driven, but were not taught how to disaggregate data in their training programs. There was a need for teachers to be trained in data disaggregation. The research question was: "How will the implementation of faculty development workshops improve the disaggregation of student scores on the Standards of Learning Assessment, targeted classroom instruction, and communication between the testing grade levels at the research site?" The researcher performed an action research cycle from planning through interventions. The action research cycle consisted of one pre-step and four additional steps: (a) constructing and planning (prestep), (b) planning action, (c) taking action, and (d) evaluating action. Participants were recruited from the testing grade levels (3-5), and the sample consisted of eight teachers. Participants were interviewed and observed while teaching before, during and after the interventions. Meetings were also held with the principal before, during and after the interventions. Data analysis was done by coding the interviews, by using numbers to indicate patterns and themes within and among the responses. The analysis of the data from the observation tool, and meeting notes was completed by compiling the information and displaying it on tables. The study showed that most teachers were not taught to disaggregate data and had been using methods that they had devised. The results revealed that there was a notable improvement in how the participants disaggregated their data in a more uniform manner, communicated more information to other testing grade level teachers, and used information from the assessment for targeted classroom instruction. The principal of the research site noted an increase in data being uniformly disaggregated, communication increased between the testing grade levels, and information from the data used for targeted classroom instruction. A recommendation for future research would be to study the impact of including data disaggregation in teacher training programs on educational organizations. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]